Hydrogen availability
Discussion
anonymous said:
[redacted]
NOTES:1) the charging info they reference is rather out of date. The report suggests 85 to 92% charging efficiency, based on measured charger data from the INL. When you go looking for the raw data it turns out the most modern car tested is a 2014 Tesla Model s (that's a 6 year old model) and that has a 91% charging efficiency. The last car i measured, a much more current EV (can't say which sorry for confidentiality reasons) had a measured AC charging efficiency of 97% because it used a modern multiphase Silicon Carbide ZVS resonant rectifier. So your "15% charging losses" are for a relevant modern EV more like 3% an even for a 6 year old tesla they are 9%.
2) EVs get slightly MORE efficient in cold weather because the electrical resistance of their electrical conductors falls as temperature falls But there range drops because like all cars their roadload increases (colder air is more dense, cold tyres have a greater hysteresis), which increases consumption, and the cold battery has a lower available charge storage capacity so they have less available energy to use. Cabin heating loads also significantly increase consumption because there is little waste heat to use for that purpose.
This is of course the same for FCV's but actually somewhat potentially worse because the FCV may actually have to heat it's incomming fuel cell air to avoid it freezing into a solid lump of ice at sub zero temperatures. The battery and motor in a FCV of course get slightly more efficient as per the BEV. As the road load is the ultimate (final) consumer of energy, and the total input energy is the roadload times the conversion efficiency, a FCV experiences a greater net increase in consumption because it's efficiency is lower overall when compared to a BEV.
anonymous said:
[redacted]
I bring you back to the bold part of my post.People like you ruin debate and discussion when you can't accept there's another opinion. You get an answer from me with information that supports why I don't agree entirely with you and you don't like it because it isn't the answer you are looking for. You cut out the substance of my post, ignore it and solely focus on how I dare challenge your statement.
It's as simple as that.
JonnyVTEC said:
dvs_dave said:
Sigh....ok
Your straight up obstinance and unwillingness to accept any facts contrary to your belief set is simply exhausting and has ruined this otherwise quality debate.
Well summed up where I’m at. Your straight up obstinance and unwillingness to accept any facts contrary to your belief set is simply exhausting and has ruined this otherwise quality debate.
The devil’s advocate position can be useful to give others the opportunity to respond with reinforcing information, having your position challenged is not a bad a thing as it forces you to ‘check your work’. Interestingly for me, there have been several things that he has unearthed that I wasn’t aware of, but these have only strengthened the case for batteries in my opinion!
Many of the posters here are engineering-minded and look at problem solving in a logical way. This of course is necessary in a professional environment where decision making is measurable and accountable.
But not everybody thinks like that. I don’t mind hearing alternative perspectives, and he is correct that he has a right to his opinion.
That doesn’t mean I agree with these opinions, otherwise we’d both be wrong.
https://www.autocar.co.uk/car-review/toyota/mirai/...
Not sure on the price - sub-headline says 66k but text and summary says estimated 50k...
Not sure on the price - sub-headline says 66k but text and summary says estimated 50k...
AmitG said:
https://www.autocar.co.uk/car-review/toyota/mirai/...
Not sure on the price - sub-headline says 66k but text and summary says estimated 50k...
Another little article I've read say they have made the stack 10% more efficient and also smaller.Not sure on the price - sub-headline says 66k but text and summary says estimated 50k...
It did suggest the lower price.
The car looks much better than the MK1 too!
I'd like to see the official figures though......
Max_Torque said:
2) EVs get slightly MORE efficient in cold weather because the electrical resistance of their electrical conductors falls as temperature falls But there range drops because like all cars their roadload increases (colder air is more dense, cold tyres have a greater hysteresis), which increases consumption, and the cold battery has a lower available charge storage capacity so they have less available energy to use. Cabin heating loads also significantly increase consumption because there is little waste heat to use for that purpose.
.
You have missed out that a battery has less effective capacity when its colder, so while it might be 'efficient' you ain't going as far..
And the effect on conductors ? The resistivity coeff is about 0.004 per degree for copper & alu, so its really bugger all for a power conductor.
anonymous said:
[redacted]
1950kg according to Autocar? Isn't that even heavier than the outgoing model and about 100kg more than a Model 3? I thought FCEV were supposed to be lighter than EVs?I guess there are design compromises where you're just reworking an ICE vehicle (it's based on a Lexus), rather than building an FCEV from a blank page though.
rscott said:
1950kg according to Autocar? Isn't that even heavier than the outgoing model and about 100kg more than a Model 3? I thought FCEV were supposed to be lighter than EVs?
I guess there are design compromises where you're just reworking an ICE vehicle (it's based on a Lexus), rather than building an FCEV from a blank page though.
In fairness the new Mirai is a very big car (I believe it's based on the Lexus LS platform) - so the comparison should really be with a BEV that is Lexus LS sized...maybe the forthcoming electric XJ?I guess there are design compromises where you're just reworking an ICE vehicle (it's based on a Lexus), rather than building an FCEV from a blank page though.
(And even then, lots of factors influence weight - sound deadening, aluminium versus steel etc....I have no idea whether FCEV should be lighter than BEV, but we really need to compare like with like - ideally the same car in FCEV and BEV forms...)
Gary C said:
Max_Torque said:
2) EVs get slightly MORE efficient in cold weather because the electrical resistance of their electrical conductors falls as temperature falls But there range drops because like all cars their roadload increases (colder air is more dense, cold tyres have a greater hysteresis), which increases consumption, and the cold battery has a lower available charge storage capacity so they have less available energy to use. Cabin heating loads also significantly increase consumption because there is little waste heat to use for that purpose.
.
You have missed out that a battery has less effective capacity when its colder, so while it might be 'efficient' you ain't going as far..
And the effect on conductors ? The resistivity coeff is about 0.004 per degree for copper & alu, so its really bugger all for a power conductor.
And yes, the drop in resistivity is tiny, but it important to note that it is not a loss of efficiency in the powertrain, unlike for an ICE (and sometimes for a HFC depending on temp)
AmitG said:
rscott said:
1950kg according to Autocar? Isn't that even heavier than the outgoing model and about 100kg more than a Model 3? I thought FCEV were supposed to be lighter than EVs?
I guess there are design compromises where you're just reworking an ICE vehicle (it's based on a Lexus), rather than building an FCEV from a blank page though.
In fairness the new Mirai is a very big car (I believe it's based on the Lexus LS platform) - so the comparison should really be with a BEV that is Lexus LS sized...maybe the forthcoming electric XJ?I guess there are design compromises where you're just reworking an ICE vehicle (it's based on a Lexus), rather than building an FCEV from a blank page though.
(And even then, lots of factors influence weight - sound deadening, aluminium versus steel etc....I have no idea whether FCEV should be lighter than BEV, but we really need to compare like with like - ideally the same car in FCEV and BEV forms...)
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